3 results
On oral calcifications: Tartar and Pulp stones
- A.J. Anjos, P. Nolasco, J.M. Aquino Marques, A.P. Alves de Matos, P.A. Carvalho
-
- Journal:
- Microscopy and Microanalysis / Volume 21 / Issue S6 / August 2015
- Published online by Cambridge University Press:
- 10 September 2015, pp. 66-67
- Print publication:
- August 2015
-
- Article
-
- You have access Access
- Export citation
On oral calcifications: sialoliths, dental calculi and tonsilloliths
- A.J. Anjos, P. Nolasco, J.M. Aquino Marques, F. Cabrita, M.F.C. Pereira, A.P. Alves de Matos, P.A. Carvalho
-
- Journal:
- Microscopy and Microanalysis / Volume 19 / Issue S4 / August 2013
- Published online by Cambridge University Press:
- 06 August 2013, pp. 23-24
- Print publication:
- August 2013
-
- Article
-
- You have access Access
- Export citation
-
The oral cavity is susceptible to several calcifications such as salivary calculi (sialoliths), dental calculus (tartar) and tonsillar concretions (tonsilloliths). Although several individual studies had been already carried out, a comprehensive morphological and elemental comparison between them is still missing.
Sialoliths are most commonly found in the submandibular glands and are composed of regions rich in Ca and P minerals, namely hydroxyapatite, whitlockite and brushite, and regions consisting of organic matter with high-sulphur content. These regions are organized in alternating concentric layers. Several bacterial species have also been identified in sialoliths microstructure showing that infection occurs recurrently throughout the stone formation.
Generally, tartar presents an inorganic structure rich in Ca and P minerals, such as brushite, octacalcium phosphate, hydroxyapatite and whitlockite, and an organic matrix, mainly constituted by aerobic bacteria and yeast or just anaerobic bacteria.
Tonsilloliths occur most commonly on the crypts of the palatal tonsils and are composed of a mixture of organic matter, namely bacterial cells and epithelial debris, as well as inorganic material rich in Ca and P minerals such as hydroxyapatite. Volatile sulphur compounds produced by anaerobic bacteria are usually associated to these, in general, innocuous structures.
The current study involved the ultrastructure and chemical characterization of the calcified structures by scanning electron microscopy (SEM) combined with energy dispersive spectroscopy carried out with a JEOL JSM 7001F instrument with an INCA pentaFetx3 Oxford spectrometer operated at 15 kV. Higher resolution characterization has been performed by transmission electron microscopy (TEM) using a H8100 Hitachi instrument operated at 200 kV. SEM samples were prepared following metallographic procedures, whereas TEM samples were obtained following standard biological sample preparation procedures.
The results show that sialoliths present the most complex structure, with a central core surrounded by concentric layers, while tartar and tonsilloliths do not have a distinctive architecture (Figures 1 (a), 2 (a) and 3 (a). At higher magnifications, layered structures, as well as crystals could be found in sialoliths and tartar (Figures 1 (b) and 2 (b). Bacteria were common in all the calcified structures, although in tonsilloliths their abundance is higher (Figure 3 (b)). All calcifications have similar elemental constitution, with Ca and P, indicating the presence of calcium phosphates (Figures 1 (c), 2 (c) and 3 (c). Sulphur was also found associated with the organic matter in sialoliths and tonsilloliths, though the amounts found in the latter were much smaller than initially expected.
Based on the similarities found, new correlations between these calcification will be available. For instance, the mineralization process described in tartar can help understand the similar processes occurring in sialoliths and tonsilloliths, while the association between bacteria and sulphur in tonsilloliths can be a clue for their presence in sialoliths.
The work was carried out with financial support of the Portuguese Foundation for Science and Technology through PTDC/SAU-ENB/111941/2009 and PEst-OE/CTM-UI0084/2011 grants.
Structural typologies of salivary calculi
- P. Nolasco, A.J. Anjos, J.M. Aquino Marques, F. Cabrita, M.F.C. Pereira, A.P. Alves de Matos, P.A. Carvalho
-
- Journal:
- Microscopy and Microanalysis / Volume 19 / Issue S4 / August 2013
- Published online by Cambridge University Press:
- 06 August 2013, pp. 29-30
- Print publication:
- August 2013
-
- Article
-
- You have access Access
- Export citation
-
Several theories have been put forward regarding the aetiology and pathogenesis of salivary calculi, although a comprehensive understanding of the nucleation and growth mechanisms involved in the formation of these structures is still lacking.
In general, sialoliths present one core partially or highly mineralized surrounded by concentric layers of organic and mineralized matter that alternate in succession following a chronologic sequence. The layers consist of fine mineralized strata intercalated with fine organic ones and threaded globular structures with variable degrees of mineralization.
The exact mechanism involved in the genesis of sialoliths remains largely unknown, theories defending an initial organic nidus or an initial precipitation of minerals, with subsequent deposition of organic and inorganic layers, can be found in the literature. Nevertheless, it remains object of discussion the etiologic factors responsible for the formation of the first nidus or the initial precipitation, since infection, inflammation of the gland, viscous nature of the mucous secretions or naturally existing sialomicroliths have all have been implicated.
Aiming at an exhaustive systematization of salivary calculi morphogenesis, their morphology has been studied by micro-computed tomography (bCT) and scanning electron microscopy (SEM). CCT studies were done on as-extracted dried samples using uCT SkyScan 1172 instrument with a 1.3 Megapixel camera, operated at the maximum available power of the source (10W). Radiographs acquisition was performed with a rotational step in the 0.70-1° range, until a maximum of 180º, with an exposure time in the 3.1-5 s range. Microscopy observations were carried out with backscattered electron (BSE) signals using a JEOL JSM 7001F operated at 15 kV, samples were previously prepared following metallographic procedures.
The submandibular and parotid calculi investigated presented similar growth patterns, which can follow either concentric (Figure 1) or perturbed-growth typologies (Figure 2), although in most situations a gradation between them has been found. Nevertheless, a single well-defined core constituted by material with low mineralization was frequently present, supporting the nucleation hypothesis of an initial organic nidus.
The combination of TCT with SEM enabled a comprehensive characterization of the sialoliths: (i) the former technique allowed for a precise localization of the core and other morphological features within the calculus volume, while (ii) investigation of details at higher resolution could be achieved with the latter method. However, due to the friable nature of the sialoliths, handling during sample preparation results often in material loss (compare (a) and (b) in both Figures).
The work was carried out with financial support of the Portuguese Foundation for Science and Technology through PTDC/SAU-ENB/111941/2009 and PEst-OE/CTM-UI0084/2011 grants.